The woman who won Wednesday night's massive $758.7 million Powerball jackpot has come forward to claim the prize.

"I just want to sit back and relax," Mavis L. Wanczyk said at lottery headquarterswhen asked what's the first thing she'll do with the money. "I had a pipe dream and my pipe dream came true."

It's the second-largest Powerball jackpot in U.S. history but the largest to be won by a single ticket.

Wanczyk, a 53-year-old resident of Chicopee, Massachusetts, said she is a regular lottery player, who regularly plays keno with her mother, stepfather and a friend. Their lucky number is 4 — the Powerball number in Wednesday night's draw. The other five numbers drawn were 6, 7, 16, 23 and 26.

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(Published Wednesday, Aug. 23, 2017)

Wanczyk discovered she'd won when finishing her shift at Mercy Medical Center in Springfield, where she works in patient care. She said she was talking to a firefighter she works with and didn't initially believe him when he told her she'd won.

"He goes, 'Sign that ticket now,'" Wanczyk recalled, adding that he followed her home to make sure she was safe.

She said the reality of her winning was hitting her at the news conference she gave at 1 p.m. ET, and still had lots of planning to do. She plans to pay off a new car she purchased last year.

Lottery officials say she chose to take a lump sum payment of $480 million, or $336 million after taxes.

A mistake by the Massachusetts State Lottery injected a little extra drama into the drawing hours after the drawing Wednesday night when lottery officials initially bungled their announcement and gave the wrong shop and location.

The lottery corrected the site where the single winning ticket was sold to Chicopee, Massachusetts. Overnight, they had announced the winning ticket was sold at a shop in Watertown, just outside Boston.

But shortly before 8 a.m., the lottery said it had made a mistake, and that the winning ticket was sold at the Pride Station & Store in Chicopee, about halfway across the state.

The store in Watertown did sell a ticket that won a $1 million prize. Reporters had descended on the store hours before it opened around 6:30 a.m.

"Still happy, but what can we do," Marjeet Paaur Khan, an owner of that store, told NBC Boston.

Mike Donatelli, a spokesman for the Pride Station & Store in Chicopee, says they were told shortly before 8 a.m. that the store had actually sold that ticket.

Massachusetts State Lottery Executive Director Michael Sweeney said the store will pocket $50,000 for selling the jackpot winner, though owner Bob Bolduc said the money would all go to local charities.

"We support all local charities anyway, so they'll just get a little bonus," Bolduc said.

Powerball is played in 44 states plus Washington, D.C., Puerto Rico and the U.S. Virgin Islands, all of which collectively oversee the game. Drawings are held twice a week. Five white balls are drawn from a drum containing 69 balls and one red ball is selected from a drum with 26 balls. Players can choose their numbers or let a computer make a random choice.